Commutator arrangements



July 26, 1960 G. ULBRICH 2,946,908 COMMUTATOR ARRANGEMENTS Filed Sept.4, 1956 INVf/VME; Gerhard Ulbrich United States Patent J COMMUTATORARRANGEMENTS Gerhard Ulbrich, Stuttgart, Germany, assignor to RobertBosch, G.m.b.H., Stuttgart, Germany Filed Sept. 4, 1956, Ser. No.607,707 Claims priority, application Germany Sept. 8, 1955 Claims. 01. s234 The present invention relates to electric motors of the type used,for example, in automobiles and other engine driven vehicles.

More particularly, the present invention relates to the manner in whichthe armature wires of such a motor are connected to the severalcommutator bars of the motor.

One of the objects of the present invention is to provide a superiorelectrical contact between the armature wires and the several commutatorwires.

Another object of the present invention is to connect the armature wiresto the commutator bars in a manner capable of withstanding centrifugalforces resulting from high speed rotation of the armature.

A further object of the present invention is to provide a structurecapable of accomplishing the above objects and at the same time composedof simple and ruggedly constructed elements which are very reliable inoperation.

With the above objects in view the present invention mainly consists ofan electric motor which includes a commutator ring having a pluralityof. electrically conductive commutator bars parallel to and distributedabout the axisof an armature which carries the commutator ring, thesebars being spaced and insulated from each other. Each bar has an enddirected toward the armature and formed with a pair of slotssubstantially parallel to each other and extending substantiallyradially from the axis of the. armature. A pair of armature wires arelocated over each bar at its end adjacent the armature with one of thesewires located between the bar and the other of the wires. Anelectrically conductive elongated connector has a pair of legsrespectively extending through said slots and embracing the wires forholding the latter together and in operative relationship with each bar.

The novel features which areconsidered as characteristic for theinvention are set forth in. particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings, inwhich:

Fig. l is a fragmentary axial sectional elevational view of a commutatoraccording to the present invention; and

Fig. 2 is an end view of the structure of Fig. 1 as seen from the leftside thereof.

The commutator includes a ring 10 of pressed electrically non-conductivematerial in which the individual electrically conductive commutator bars11 are anchored by the hook-shaped portions 12 of each bar which areembedded in the insulating material of the ring 10, the commutator barsbeing distributed about and parallel to the axis of the unillustratedarmature which carries the commutator, and these bars being parallel toand insulated from each other. Portions 16 of the ring 10 arerespectively located between the bars 11, and the end of the ring 10adjacent the armature is formed with an annular cutout at the exteriorof the ring 10. A plurality of partitions 14 are respectively jointed tothe portions 16 of the ring 10 and are carried by the latterrespectively in planes extending radially from the axis of the armature,these partitions 14 being made of electrical insulating material andextending across the annular cutout at the end of the ring 10 to dividethe annular cutout into a plurality of spaces 13 separated from eachother by the insulating partitions 14. The bars 11 respectively havefree ends which respectively extend into the spaces 13, and the end faceof each bar 11 is formed with a pair of slots 17 which are parallel toeach other and which extend substantially radially from the axis of thearmature. In other words, the pair of slots 17 of: each bar 11 do notextend radially from this axis but extend almost radially from thisaxis, and each pair of slots are parallel to each other.

A. connector 18 made in one piece from a strip of electricallyconductive sheet metal or the like and having substantially theconfiguration of a ladys hair pin is associated with each bar 11 and hasa pair of legs respectively located in the pair of slots 17 of each bar11, the thickness of this strip being substantially equal to the widthof the slots. As a result, each leg of each connector 18 is inelectrical contact with the bar 11 to which itis connected at both sidefaces and one edge face of each portion of each leg which is located ina slot 17, so that a very large area of contact is provided. Theoutwardly extending portions of the legs of each connector 18 locatedoutwardly beyond each bar 11 embraces a pair of wires 19 and 20extending from the windings. of the unillustrated armature, these wiresbeing in elec trical contact with each other and with the connector 18,and the wires 19 respectively engaging directly andbeing in electricalcontact with the bars 11. Only the ends of the wires 19 and 20 areembraced by the connectors 18. The pairs of wire ends 19 and 20 aredipped in solder so as to provide a good electrical conduction betweeneach pair of wires and the connector 18 as well as between the wires 19and the bars 11, respectively. Moreover, the solder provides a superiormechanical connection between the parts. It will be noted that with thestructure of the invention even when the armature rotates at high speedthe parts will be able to reliably resist the action of the centrifugalforces.

It will be understood that each. of the elements described above, or twoor more together, may also find a useful application in other types ofcommutators differing from the types described above.

While the invention has beenillustrated and described as. embodied in.commutator connections, it is not in.- tended to be limited to thedetails shown, since various modifications and structural changes may bemade without departing in any way from the spirit of the presentinvention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In an electric motor, in combination, a commutator ring having aplurality of electrically conductive commutator bars parallel to anddistributed about the axis of an armature which carries said ring andspaced and insulated from each other, each of said bars having an endface directed toward said armature and formed with Patented July 26,1960 a pair of slots substantially parallel to each other and extendingspaced from each other and the side faces of said bar substantiallyradially from the axis of the armature and substantially normal to saidend face into each bar, said slots defining between themselves a centralend portion in each bar; a pair of armature wires located over each barat its end adjacent the armature with one of said wires directlyengagingthe outer face of said bar and located between the latter and the otherof said wires and engaging the latter; and an electrically conductiveloop-shaped connector having a pair of legs respectively extendingthrough said slots and embracing said central end portion and said Wiresfor holding the latter together and in operative relationship with eachbar.

2. In an electric motor, in combination, a commutator ring having aplurality of electrically conductive commutator bars parallel to anddistributed about the axis of an armature which carries said ring andspaced and insulated from each other, each of said bars having an endface directed toward said armature and formed with a pair of slotssubstantially parallel to each other and extending spaced from eachother and the side faces of said bar substantially radially from theaxis of the armature and substantially normal to said end face into eachbar, said slots defining between themselves a central end portion ineach bar; a pair of armature wires located over each bar at its endadjacent the armature with one of said wires located between said barand the other of said wires; and an electrically conductive loop-shapedconnector having a pair of legs respectively extending through saidslots and embracing said central end portion and said wires for holdingthe latter together and in operative relationship with each bar.

3. In an electric motor, in combination, a commutator ring having aplurality of electrically conductive commutator bars parallel to anddistributed about the axis of an armature which carries said ring andspaced and insulated from each other, each of said bars having an endface directed toward said armature and formed with a pair of slotssubstantially parallel to each other and extending spaced from eachother and the side faces of said bar substantially radially from theaxis of the armature and substantially normal to said end face into eachbar, said Slots defining between themselves a central end portion ineach bar; a pair of armature wires located over each bar at its endadjacent the armature with one of said wires located between said barand the other of said wires; and a loop-shaped electrically conductiveonepiece metallic connector having a pair of legs respectively extendingthrough the slots of each bar and embracing said central end portion andsaid wires for holding the latter together and in operative relationshipwith said bar.

4. In an electnic motor, in combination, a commutator ring having aplurality of electrically conductive commutator bars parallel to anddistributed about the axis of an armature which carries said ring andspaced and insulated from each other, each of said bars having an endface directed toward said armature and formed with a pair of slotssubstantially parallel to each other and extending spaced from eachother and the side faces of said bar substantially radially from theaxis of the armature and substantially normal to said end face into eachbar, said slots defining between themselves a central end portion ineach bar; a pair of armature wires located over each bar at its endadjacent the armature with one of said wires located between said barand the other of said wires; and a loop-shaped electrically conductiveone-piece metallic connector having a pair of legs respectivelyextending through the slots of each bar and embracing said central endportion and said wires for holding the latter together and in operativerelationship with said bar, saidw-ires and said connector and commutatorbar associated therewith being soldered to each other.

5. In an electric motor, in combination, a commutator ring composed of atubular support of electrically nonconductive material having an endface directed toward an armature which carries said ring formed with anouter annular cutout and said ring including a plurality of commutatorbars parallel to and distributed about the axis of the armature andcarried by said tubular support in spaced parallel relationship to eachother, each of said bars having a free end portion extending into saidcutout and having at said free end portion an end face formed with apair of slots substantially parallel to each other and extending spacedfrom each other and the side faces of said bar substantially radiallyfrom the axis of the armature, said slots defining between themselves acentral end portion in each bar; a pair of armature wires located overeach bar at its end adjacent the armature with one of said wires locatedbetween said bar and the other of said wires; and an electricallyconductive elongated connector having a pair of legs respectivelyextending through said slots and having a connecting portion integralwith said pair of legs and located in said cutout closely adjacent tosaid free end portion, said elongated connector embracing said free endportion and said wires for holding the latter together and in operativerelationship with each bar.

References Cited in the file of this patent UNITED STATES PATENTSGermany Oct. 22,

